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Of the Tasman Glacier

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Of the Tasman Glacier 1 ICE DYNAMICS OF THE HAUPAPA/TASMAN GLACIER MEASURED AT HIGH SPATIAL AND TEMPORAL RESOLUTION, AORAKI/MOUNT COOK, NEW ZEALAND A THESIS Presented to the School of Geography, Environment and Earth Sciences Victoria University of Wellington In Partial Fulfilment of the Requirements for the Degree of MASTERS OF SCIENCE By Edmond Anderson Lui, B.Sc., GradDipEnvLaw Wellington, New Zealand October, 2016 2 TABLE OF CONTENTS SIGNATURE PAGE .................................................................................................................... TITLE PAGE ............................................................................................................................................... 1 TABLE OF CONTENTS .......................................................................................................................... 2 LIST OF FIGURES ..................................................................................................................................... 5 LIST OF TABLES ....................................................................................................................................... 9 LIST OF EQUATIONS ...........................................................................................................................10 ACKNOWLEDGEMENTS ....................................................................................................................11 MOTIVATIONS ........................................................................................................................................12 ACRONYMS ..............................................................................................................................................12 ABSTRACT ................................................................................................ 13 CHAPTER ONE: LITERATURE REVIEW .............................. 14 1.0 INTRODUCTION ........................................................................................................ 14 1.1 GLOBAL TRENDS AND SLR PROJECTIONS .........................................................16 1.1.1. Sea-level Rise impacts ..............................................................................................................18 1.1.2. Glaciers as repositories of fresh water ..................................................................................18 1.1.3. Para-glacial sedimentation impacts ........................................................................................19 1.2 DYNAMICS OF CALVING GLACIERS ...................................................................... 20 1.2.1. Introduction ...............................................................................................................................20 1.2.2. Iceberg Calving..........................................................................................................................20 1.2.3. Controls on the calving process .............................................................................................22 1.2.3.1. A hierarchical approach ...................................................................................................24 1.3 METHODOLOGY REVIEW ....................................................................................... 25 1.3.1. Introduction ...............................................................................................................................25 1.3.2. Imaging geometry .....................................................................................................................25 1.3.3. Digital Image Correlation (DIC) techniques ........................................................................28 1.3.3.1. How image subsets are tracked through DIC .............................................................29 1.3.4. Why oblique photogrammetry? ..............................................................................................30 1.4 THESIS OBJECTIVES ................................................................................................ 31 CHAPTER TWO: STUDY SITE .................................................. 32 2.0 INTRODUCTION ....................................................................................................... 32 2.0.1. The role of glacial debris .........................................................................................................32 2.0.2. Lake surveys to date .................................................................................................................33 2.0.3. Gaps in the literature ................................................................................................................33 2.0.4. Calving processes ......................................................................................................................33 3 2.1 GEOMETRY OF THE TASMAN GLACIER .............................................................. 35 2.2 MELTING AND DOWNWASTING OF THE TASMAN GLACIER ........................ 37 2.2.1. Debris cover and rates of ablation .........................................................................................38 2.3 CONTEMPORARY LAKE FORMATION AND CALVING ...................................... 39 2.3.1. Buoyancy-driven Calving .........................................................................................................40 2.3.2. Other forms of Calving ...........................................................................................................42 2.4 TERMINUS RETREAT RATES SINCE 1890 (UR) ................................................. 43 2.5 SURFACE ICE VELOCITY (UI) ................................................................................ 44 2.6 CALVING RATES (UC) .............................................................................................. 48 2.7 REGIONAL CLIMATE .............................................................................................. 50 2.7.1. Regional circulation and precipitation trends ......................................................................50 2.7.2. Temperature sensitivity and future projections ...................................................................52 2.7 INVESTIGATION AIMS ............................................................................................. 53 CHAPTER THREE: METHODS ................................................ 54 3.0 INTRODUCTION ....................................................................................................... 54 3.1 PHASE ONE: DATA ACQUISITION ......................................................................... 56 3.1.1. Equipment Setup ......................................................................................................................56 3.2 PHASE TWO: IMAGE SELECTION .......................................................................... 59 3.2.1. Image Stabilisation ....................................................................................................................59 3.2.2. Temporal Selection of Images ................................................................................................61 3.2.3. Summary of Phase Two ...........................................................................................................64 3.3 PHASE THREE: POST PROCESSING AND RESULTS .......................................... 65 3.3.1. Introduction and Framework .................................................................................................65 3.3.2. Intrinsic Camera Parameters ...................................................................................................66 3.3.2.1. Intrinsic Parameters from SfM ......................................................................................68 3.3.3. Extrinsic Camera Parameters ..................................................................................................68 3.3.4. Ground Control Points (GCPs) .............................................................................................69 3.3.4.1. GCP Equipment ...............................................................................................................70 3.3.4.2. GCP Sites ...........................................................................................................................71 3.3.5. Summary of Batch Allocation ................................................................................................74 3.3.6. Estimating extrinsic parameters using GCPs .......................................................................75 3.3.6.1. SolvePnP ............................................................................................................................76 3.3.6.2. Optimisation of GCPs .....................................................................................................76 3.3.6.3. Limitations and discussion of GCP methodology ......................................................77 3.3.7. Summary of Extrinsic Camera Parameters...........................................................................78 3.3.8. Framework for Measurement One: Velocities ....................................................................79 3.3.8.1. Measuring pixel displacements and direction of flow ................................................80 3.3.8.2. Grayscale conversion .......................................................................................................80 3.3.8.3. DIC in Matlab ...................................................................................................................81
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